1. Field of the Invention
The present invention relates to devices, systems, and methods for delivering an intraocular lens into an eye. More particularly, the invention relates to devices, systems, and methods in which the intraocular lens is loaded from the front end of the device.
2. Description of the Related Art
Intraocular lenses (IOLs) may be implanted in the eye of a subject to replace the natural crystalline lens or to otherwise modify the vision of an eye containing either the natural lens or another IOL. IOLs often include an optic and one or more flexible fixation members or haptics extending from the optic to secure and center the optic within the eye. When the IOL replaces the natural lens, the natural lens must first be removed, for instance, using a phacoemulsification system. The IOL is then generally implanted using an insertion apparatus or device that rolls, folds, or otherwise configures the lens for delivery through a small incision in the eye in a way that reduces trauma and expedites post-surgery healing.
Inserters for delivering IOLs into the eye generally employ a cartridge having a hollow insertion tube or cannula through which the folded IOL is passed using a pushrod. The inserter may be designed for reuse, in which case the inserter components are usually made of some type of metal alloy. Alternatively, disposable inserters may be used that are made of less expensive materials, such as plastics, and that remain in a sterile package until ready for use. The pushrod and insertion tube may be designed to advantageously provide the surgeon precise control of the IOL as it is place inside the eye, for example as disclosed in U.S. Pat. No. 6,093,193, herein incorporated by reference.
One problem encountered with existing inserters is difficulty in loading the IOL into the inserter. The IOL is typically about 10 to 15 mm in diameter, about a millimeter thick, and is manually delivered from a sterile container to a cartridge or inserter using forceps or tweezers. Manual transfer of the IOL presents difficulties in maintaining both sterility of the IOL and the correct orientation of the IOL within the cartridge or inserter. Improper orientation of the IOL can cause damage to the IOL or inadequate surgeon control during delivery into the eye.
These problems may be mitigated by preloading the IOL at the manufacturer into a cartridge or container that is designed to be directly attached to the inserter. The cartridge or container may be attached to the inserter either at the manufacturer or by the user prior to surgery. In either case, the IOL is generally not stored directly in the inserter, since it is desirable that the IOL be maintained during storage in an unstressed state in order to prevent undesirable, permanent deformation of the optic element. Thus, some type of loading process is still generally necessary to transfer the IOL into the inserter.
Various means and mechanisms are disclosed in the art for manipulating the IOL from a state suitable for storage of the IOL to a state suitable for delivery of the IOL into the eye of a patient. Prior to transferring the IOL into the inserter, the IOL is maintained in an unstressed state inside some type of holding chamber that is attached above or to the side of a chamber that is directly in line with the pushrod. In transferring the IOL from the holding chamber and into the pushrod path, the IOL is move along an axis that is normal to the longitudinal axis of travel of the pushrod. Such designs require relatively complex mechanisms to move IOL along two substantially orthogonal axes (i.e., the transfer axis of travel and the pushrod longitudinal axis of travel). Another potential problem with such loading configurations is that the mechanisms for transferring the IOL may fail to provide adequate visibility of the IOL within the inserter. Inadequate visibility of the IOL makes it more difficult to ensure proper orientation and lubrication of the IOL prior to delivery through the insertion tube.
It would be advantageous to provide IOL insertion apparatus and methods that facilitate the transfer and/or placement of an IOL within the inserter in preparation for delivery into the eye of a subject during an ocular surgery, such as a cataract surgery.